Polyether, polyester or polycarbonate glycols at molecular weights of 650 to 5000 are usually used as soft segments in various segmented block copolymers such as polyurethanes and elastomeric polyesters. On the other hand, compounds which contain perfluoroalkyl groups of sufficient length are known to dramatically reduce surface energy in systems, giving rise to water and oil repellency as well as antisoiling properties.
Fluorine-containing polyethers of the formula: ##STR1## are disclosed in U.S. Pat. No. 3,242,218, and polyether glycols of the formula: ##STR2## are disclosed in U.K. Patent Specification No. 782.615. The former materials are nonfunctional compounds; consequently, they could not be used to form segmented block copolymers. On the other hand, the latter, due to the single perfluoromethyl group, provides such very marginal surface energy reduction that it is incapable of providing any effective oil or water repellency. U.S. Pat. Nos. 3,896,251, 4,046,944 and 4,540,765 disclose the preparation of polyurethanes, using glycols of the gene al formula: ##STR3## However, it is well known that monomeric glycols such as those disclosed in the latter three U.S. patents yield segmented polymers having inferior physical properties, such as tensile strength and modulus; e.g. they fail to give polyurethanes having sufficient elasticity. Monomeric glycols or diamines are usually used as curing agents or chain extenders and become part of the hard segment. On the other hand, the amorphous soft segment in form of an oligomeric ester, ether or carbonate glycol has to be long enough to equalize the hard crystalline urea or urethane segment.
U.S. Pat. No. 4,427,803 discloses using polyethers derived from 3-perfluoroalkyl-1,2-epoxy-propane in combination with other materials as mold release agents. The patentees state that their polymers are known from British Patent No. 782615 which discloses cationic polymerization of 3,3,3-trifluoro-1,2-epoxypropane or its 2-methyl analog to a high molecular weight polymer; e.g. the former is polymerized to a molecular weight in excess of 50,000. Using the British process with the monomers disclosed in the U.S. patent leads to nonfunctional cyclic ethers and/or high molecular ethers with a functionality of less than two. Because such products have little or no functionality, they apparently are well suited as mold release agents. By the same token, however, they are quite unsuitable for making useful polymers. European Patent Application 0 152 065 prepares copolymers of .OMEGA.-perfluoroalkyl-1,2-epoxyalkanes (including propane) with various other epoxy compounds. No chain transfer agent is recited in the Examples of the European Application, and as a consequence, the copolymers are of high molecular weight, making them unsuitable for incorporation into segmented block copolymers, such as polyurethanes and elastomeric polyesters (the average molecular weights are between 7050 in Example 3 and 13,600 in Example 12). In a similar fashion, water-and oil-repellent agents are described in Japanese Patent Application 46-25361, published July 22, 1971. Those agents comprise homopolymers and copolymers prepared by polymerizing 3-perfluoroalkyl-1,2-epoxy-propanes in the absence of any molecular weight control agent. As a consequence, those polymers also would be unsuitable for preparing the above-mentioned segmented block copolymers, as their molecular weights would be entirely too high.